Protective glass



Patented a. 22,- 1940 UNITED STATES PATENT OFFICE PROTECTIVE GLASS Franz Weidert, Berlin-Schoneberg, and Hans Lofiler, Berlin-Lichterfelde, Germany, aslignorl to Degea Aktiengesellschaft (Auer'gesellschaft), Berlin, Germany, a. corporation of Germany No Drawing. Application May 21, 1937, Serial No. 143,936. In Germany May 25, 1936 16 Claims.

contained a considerable addition of neodymium.

as neodymium oxide (generally in the form of commercial didymia, about 60% of which consists of neodymium oxide, NdzOs). Besides the protective efiect referred to above, such glasses containing a considerable proportion of neodymium have the valuable advantage that objects viewed. through them exhibit richer color contrasts, that is, red, green and blue appear intensified or more vivid. The absorption obtained with protective glasses of this type as made" 25 by an addition of cerium (in the form of cerium oxide), to increase the absorption within the ultra-violet region. Even this would not be sufilcient for the purposes mentioned above. Furthermore, the addition-of cerium will not reduce 30 the amount of visible light transmitted through the glass.

The object of our invention is to increase the total absorption of light, that is to say, not only to absorb the invisible ultra-violet rays efiec- 35 tively, but also to damp or tone down the transmission of the visible light rays. For instance, the absorption of the ultra-violet rays may be substantially complete, and the visible light may be reduced by absorption to, for example, 30%

40 of its original amount.

In order to obtain these results, we employ glass containing oxides of neodymium, of vanadium, and oxides of certain additional metals which correct the disagreeable greenish tint ob- 4" served when vanadium oxide is incorporated in glass without such corrective additions.

In carrying out our invention, we employ glass containing a relatively high percentage of neodymium oxide, Nd203, that is to say, a per- 50 centage sufllcient to increase the color contrasts of objects viewed through the glass. Such percentage may range from about 5% to about 50%. The desired absorptive eifects are obtained within this entire range. However, there ture and working of glass containing the higher percentages. of neodymium'oxide (above 30%), and for this reason the percentage of neodymi-- um oxide used by us ranges generally from about 5% to about 30%. 5 In addition to the neodymium oxide, our improved glass contains, as an important ingredient; an amount of vanadium (as vanadium oxide, preferably the pentoxide,: V205) sufllcient to produce the desired results, that is, an extremely strong absorption of light in the ultraviolet region and simultaneously a damping or toning down in the region of the visible light. It has been found that if this double effect is to be obtained by the addition of vanadium to glass ,1 containing a relatively high percentage of neodymium oxide, a fairly high proportion of vanadium (for instance, as V205) must be employed, say from about 0.3% to about 3%. While this will produce the desired strong absorption in the ultra-violet region and a reduction of the perviousness of the glass to visible rays,-it is accompanied by the production of a greenish stain or tint, owing to the fact that the green tint due to the additionpf vanadium oxide is sufficiently powerful to overcome or outweight the violettish tint given to the glass by the neodymium oxide. The greenish tint which the glass assumes when it contains both neodymium and vanadium in the relatively high proportions mentioned above, gives the glass an unpleasant appearance. Furthermore, such glass no longer intensifies with substantially uniform strength, all the colors viewed therethrough, lacking therefore this property which is possessed by glass containing neodymium oxide but no vanadium oxide. We may add'that glass containing vanadium but no neodymium has a. very pronounced unpleasant greenish tint and lacks the uniform strengthening of the colors just referred to above. 40

We have endeavored to produce a glass containing both neodymium oxide and vanadium oxide yet free from the detrimental and disturbvanadium, give the glass an agreeable neutral grayish or bluish-gray tint, and preserve thecon trast-heightening effect due to the presence of neodymium. It might have been assumed that such a remedy wouldbe afforded by adding some coloring matter which, considered by itself, would impart a purplish tint to the glass. We found. however, that among the various oxides-which 20 red is favored over that of other colors. weakening within the entire range of thespec- 2 2,210,122 are known as coloring .or'tinting ingredients in neodymium and vanadium)", a mixture of two ingredients, one constituted by a cobalt compound, for'instance the oxide C0104, and the other by a nickel compound, for instance the oxideNiO, or a manganese compound, for [instance the sesquioxi'de M11203. This nickel oxide,

considered by itseli, .reduc es the transmission of light within the entire range of the spectrum, but its weakening orabsorbing action is least in the region. of red'rays, so that the transmission of The trum i'sofgreat importance for the purposes of completely or nearly so, but-also to'damp the light, or absorb a portion thereof, throughout the region of visible light. .Cobalt oxide gives the glass a bluish tint, but at the same time permits substantial amounts of red to pass through. Neither nickel oxide nor cobalt oxide will cut oil or even excessively weaken that end of the spectrum opposite to the portion corresponding to the light the transmission or which is favored, and thus we preserve the property of strengthening, as uniformly as possible, all thecolors of the ob- Jects viewed, which property is possessed by the protective glasses mentioned at the beginning of this specification;

The addition of cobalt oxide, if made in suitable amounts, has the further advantage of giving the entire glass a bluish-gray tint which is particuoxide will be within the range of about 0.005%

to about 0.05%, that of nickel oxide from about 0.05% to about 0.4%, jand that of mangan oxide from about 0.05% to about 0.3%.

Three typical examples of glasses according, our invention are composed as follows:

Perhrcent Percent eel 01.0 8.2 Y 00.5 0.2 0.3

15.3 10.0 14.0 4.0 LI 4.8 11.6 V 10.0 10.5 2.5 2.5 2.0

0.1 0.01 0.1!! 0 007 o.1, an

In the three examplesfshown above, the commercial didymium oxide. contains about 60% neodymiumbxide, so that the amount of such oxide (NdzOa) in the glasses amounts to 10.92%, 11.28% or 8.76% respectively.

Each of these three glasses, A, B, and C has a neutral gray or bluish gray tint, has the same color strengthening or contrast heightening effects as neodymium glass of the prior art, absorbs ultra-violet light with practical completeness, and damps the visible light to about of its original amount.

Various modifications may be made without departing from the nature of our invention as set forth in the appended claims.

We claim:

1. A protective glass containing from about 5% to about 50% of neodymium oxide and an addition of vanadium oxide.

2. A protective glass containing from about 5% to about 50% of neodymium oxide and from about 0.3 toabout 3% of vanadium oxide.

3. A protective glass containing from about 5% to-about 30% of neodymium oxide and an addition of. vanadium oxide. our present invention, because we desire not only to suppress the transmission of ultra-violet rays 4. Aprotective glass containing from about 5% to about 3.0% of neodymium oxide and from about 0.3% to about 3% of vanadium .oxide.

5. A protective glass containing neodymium oxide, vanadium oxide, cobalt oxide, and the oxide of a metal selected from the group composed of nickel and manganese.

61A protective glass containing neodymi oxide, vanadium oxide, cobalt oxide, and nickel oxide.-

7. A protective glass containing neodymium oxide, vanadium oxide, cobalt oxide, and manganese sesquioxide.

8. A protective glass containing from about 5% to about 50% of neodymium oxide, from about 0.3% to about 3% of vanadium oxide, from about 0.005% to about 0.05% of cobalt oxide, and from about 0.05% to about 0.4% of nickel oxide. 7

9. A protective glass containing from about 5% to about 50% of neodymium oxide, from about 0.3% to about 3% of vanadium oxide, from about 0.005% to about 0.05% of cobalt oxide, and from about 0.05% to about 0.3% of manganese sesquioxide.

10. A protective glass containing from about 5% to about 50% of neodymium oxide, from about 0.3% to about 3% of vanadium oxide, from about 0.005% to about 0.05% of cobalt oxide, from about 0.05% to about 0.4% of nickel oxide, and from about 0.05% to about 0.03% of man- I ganese sesquioxide.

11."A protective glass containing from about 5% to about 30% of neodymium oxide, from about 0.3% to about 3% of vanadium oxide, cobalt oxide, and the oxide of agmetal selected from the group composed of nickel and manganese.

12. A protective glass containing neodymium oxide in a proportion which by itself would give the glass a violettish tint and which is sufilcient to increase the color contrasts of objects viewed through the glass, vanadium oxide in a proporthrough the glass, vanadium oxide in a proportion sufilcient to overcome such violettish tint and to give the glass a greenish tint, and a neutralizing addition to overcome such greenish tint and to give the glass a bluish-gray tint, said addition containing cobalt oxide and nickel oxide.

14. A protective glass containing neodymium oxide in a proportion which by itself would give the glass a violettish tint and which is sufflcient to increase the color contrasts of objects viewed through the glass, vanadium oxide in a proportion suiiicient to overcome such violettish tint and to give the glass a greenish tint, and a neutralizing addition to overcome such greenish tint and to give the glass a. bluish-gray tint, said addition containing cobalt oxide and manganese sesquioxide.

15. A protective glass containing neodymium oxide in a proportion which by itself would give the glass a violettish tint and which is suflicient to increase the color contrasts of objects viewed through the glass, vanadium oxide in a proportion suflicient to overcome such violettish tint and to give the glass a greenish tint, and a neutralizing addition to overcome such greenish tint and to give the glass a bluish-gray tint, said addition containing cobalt oxide, nickel oxide, and manganese sesquioxide.

16. A protective glass containing from about '5 to 50% of neodymium oxide, an amount of FRANZ WEIDERT. HANS LOFFLER. 

